There has been various different types of apparatus and machinery for the tachistoscopic projection of images from film strips and film material in general for assistance as a teaching aid in increasing the ability of a person to visually perceive with greater speed and accuracy and with a greater degree of visual apprehension. Structure of this type is disclosed in U.S. Pat. No. 2,723,591 relating to a Timed Focus Tachistoscope.
Naturally further improvement is always desirable and is particularly advantageous if costs can be materially reduced while obtaining the same and even improved results. Furthermore, it is also advantageous if a device can be developed which is adapted to be attached to conventional projectors, and obtain the same beneficial results.